Cable-armor.



UNITED STATE-s PATENT OFFICE.

HENRY R. GILSON, OF BADEN, PENNSYLVANIA, ASSIGNOR TO NATIONAL METAL MOLDING COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

CABLE-ARMOR. Y

y Patented Feb. 13, 1917.

Application 1ed0ctobery2, 1914. Serial No. 864,613.

To all whom t may concern.' f Be it known that I, HENRY R. GILsoN, re-

' siding at Baden, in the county of Beaver and State of Pennsylvania, a citizen of the United States, have invented or discovered certain new and useful Improvements in Cable-Armor, of which improvements the following is a specification. Y

My invention relates to such flexible cable armor or conduit as is formed of two helically coiled superposed strips of lmetal arf ranged tointerlock with each other and of' such shape as to permit of a relative movement of superposed coils for the purpose of bending the armor. 'Of the several elements to be considered in sucharmor, it is desirable in the first. place that it should possess a maximumdegree of flexibility without being unduly strained. -However, the relative movement of the superposed coils, which is essential to the flexibility of the arms, must be so resisted as to prevent undue elongation of the armor when subjected to a longitudinal pull. Also, it is desirable to have the armor strips of such configuration that the thickness of the armor, that is, the distance between the inner surface of the inside strip and the outer surface of the outside strip, shall be reduced to a minimum, commensurate with itsfutility and efiiciecy in other respects.

With these considerations in View, it is the object of my invention to provide an armor of inner and outer strips having such specific relative configuration as to affordl a minimum outside diameter of the armor, and a' maximum degree of flexibility thereof commensurate with the required limitations as to the permissible elongation when the armor is subjected to the tension orv pull test. In the practice of my invention I provide an armor formed of two strips, one of which is curved throughout so as to' be arcuate in cross section, and the other consisting-solely of a flat base or body portion with its opposite edges bent at less than a right angle thereto. l

In the accompanying sheet of drawings I have illustrated -my invention in two forms.l Figure 1 is an elevation of a short piece'of armored cable, the armor being shown partly in section; Fig. 2 an enlarged cross sectional view of the two forms of strips shown in the same relative positions as the armor of Fig.

1; and Fig. 3a view similar to Fig. 2, but showing the armor strips arranged in reverse positions.

In the disclosure of Fig.' 1 the curved or arcuate stripv 1 forms the inner wall and the flat base strip 2, 3 the outer wall of the armor which surrounds a cable 4. As will be"I readily seen, the outer strip has an extended flat base 2 and continuous edges 3 bent at less than a right angle to the base, while the inner strip 1 is continuously curved in the form of an arc of a circle. When the armor is caused to bend the edges 3 of the portions of the coils on the convex side of the bend slide upwardly upon the oppositely disposed and gradually increasing inclines of the curved strip 1, thus affording a graduall increasing resistance as the radius of the end diminishes, butpermitting of an appreciable amount of fleXure before such resista-nce becomes very great. Substantially the same degree of flexibility with increasing resistance thereto may7 be had by arranging the strips as indicated in Fig. 3, that is, the curved strip. 1I forming the outer wall and the fiat base strip 2, 3 the inner wall of the conduit. In the armor o f Figs. 1' and 2 a strip of paper 5 or other suitable material is shown between the edges 3 and the concave face of the strip 1, and in the armor of Fig. 3 a corresponding strip 58L is shown. While either form of f armor may be advantageously used, that of Figs. 1 and 2 is the most, desirable because the regularity orjsubstantial continuity of v its outer surface offers a minimum resistance when the armor is lished through small openings.

The armor may be manufactured by any suitable means in the manner 'already indi-A cated, namely, by helically coiling the inner strip with its edges turned outwardly, and the outer' strip with its edges' turnedinvwardly between the edges' of the inner strip.

will be observed that, for an when the cable is bent, the initial resistance will be slight, but will gradually increase as the radius of flexure is diminished. Also it armor having these characteristics, and being otherwise of a practical construction, the thickness of the armor wall is reduced to a minimum.

I claim as my invention:

1. A cable armor formed of inner and outer metallic strips arranged in superposed interlocking. helical coils, one of such strips having an extended flat base portion with its opposite immediately-adjoining sides bent at less than a right angle thereto to form a continuous interlocking portion, and the otherstrip being arc-shaped in cross section, said bent sides of the rst named strip resting in the concavity of the second named arc-shaped strip, and the convex side of the arc-shaped strip forming Vone wall of the armor.

2. A cable armor formed .of innerA and outer metallic strips arranged insuperposed interlocking helical coils, the inner strip being arc-shaped in .cross section with its concave side facing outwardly, and the outer strip having an extended flat base portion with its Opposite immediately adjoining sides bent at less than a right angle thereto to form a continuous interlocking portion, said sidesr resting in the concavity of the inner strip.

In testimony whereof I have hereunto set my hand. y

' HENRY R. GILSON. Witnesses:

PAUL N. CRrroHLow, FRANCIS J. ToMAssoN. 

